Pressure fluid driven tool



R. R. BUTTS Dec. 31, 1946.

PRESSURE FLUID DRIVEN TOOL Filed Feb. 26, 1942 INVENTOR. fife/MM E flu is BY WW2??? Patented Dec. 31, 1946 s nz 9f. 4 e"?! 1 1 h'n l piece member Of met forlf from bne Of the stronger brees ur t mayvbe; made terialz-d'i's cast. ;..rIt holce 01 materials o ,elargezdegre and oldedi plastic a-material I my; ot;.-g a-ndi sspeed -xot 0f the barrel ilnwardlyijltowards the rear of cylindrical portion l0 and it communicates with the inside of the bronze bearing liner forming an 99 ne nrheiei 521M114; "o nards the rear en d of M h fl tbgether ,ae n x of t e r001 9i h ldin he :snflnss; in I nli rm s n action The pi slt'on wall is provided ledh le andyh 33 respectlyely. ,In #QQ E lQt v-Qi piece ll of the trigger and convert such pressure I f anassas into a downward movement of rod-fl'which unseats ball valve 35: against theeresistance oi v its spring to admit fluid: pressure-from ausuitable source (not shown) by way'of' the nipple: 31E

From the foregoing itpwill beapparent. that-the conveniently'shaped and balanced-tool is subject'- to easy control by the hand otthe" user'who manipulates the -tool.- The operati'onof the struc- 4" work. By an lnitiallyglight. pressure oi'j the entire device; while'iholding the triggersplece'fl in, the

user'may proceedtopositionethe tool=without deliveringanyimpact-whatever. When. the'tool is ture thus far'd'escribed isas iollow'si" Assuming the trigger piece 4| to be-depressed and; the ballvalve 35-unseated; allowingithefiow of pressure:

will initially enter'annular groove-23' becauserzthe; springs lltend. to position piston ll sothat said,

groove is in at least partialregistry with theport holes 3| intothe hollow'interi'orNiofthepiston and therear end of .the cylinder bore constituted by part of the liner [2* and thewell 131'. Thispressure rapidly. urgespistonrfll forwardly 'and in doing so exerts increasing tensionfion the springs 21; piston is precludedfrom' compression by theprovision of such vents as 2i and? When the" forward wall 26.01 the annular groove reaches-- exhaust ports 20, the fluid-pressure; which has built up behind the" piston, is exhausted with great rapidity" and at the same" times: theskirt Air" in the" cylinder ahead? of the portionof the piston has closediofl the ln-let' port' ll; The exhaustof the built up 'pressure'through exhaust ports 20 isfvery-"iast and, I--have-iound, on' prolonged continuous operation :.of the tool, that the barrel remains substantially coldid'espite an almost incredible speed of reciprocation: This; is apparently due to the'expansi'on of the rapidly unloadedpressures which'are built-211p in: thextool; functioning" in accordancewith' Well kn0wn"prin--- cipies of refrigeration.

The piston 24' has agroove lli'n which an- 011- less ring (not shown) may optionally ,be used At its forward end" the plstona has an; integralimpact boss which'm'oves'irom. the position shown in Fig; 1' to about theiront end 46 0i the barrellli on the power stroke'ofthe piston.

On the i'ront'of' the ban-e1 Il a sleeve lT'is-re movablysecured; as by screws II: Thesleeve 41 has an internalannular shoulder l9, thGzCGIl ter bore 500! which slidably receives the reduced end ii of a'tool'holder E2 A=--"coili spring Misunrounds the end'Si of the t'oolhold'er'and the ends of the springabut the shoulder flof the: sleeve and shoulder 54' of the toolholder respectively, thus yielclablyurgingthe' end'of the reduced' 'portion ll out of the'range-ofthe impact boss during reciprocation of. the-piston.

A screw-stud Iii-insleevefl has its end 'ext'end insinto a: longitudina1.,slot "*in tool holder-152"" and permitsgthe toolholder to. be. shiitedi bacit in the sleeve as the user'pushes thedevice toward the work against the resistance. 01'. sprin ll. The; device is thus. capable of positioning the endioi portion 51 at an: optimum position to-receive. the. most eilfective impact rrom'the piston. The-holder 52 has a socket 51 in which atool such asa riveting tool 58-is removablyr'etained; A sprin'ga pressed ball in holder [3 enters aroove Slain the tool to effect a, simple and.' effective removable connection. I

In use as a rivetinggurr" (as. illustratedi the hollow heading cup Iii-in the inserted toolmay-b'ea positioned over the-endof a rivet to be headedup and is then yieldably held in ac'entralized position as the user presses the device toward the properly positioned: the user: merelypushes' the work whileathe; piston. is -.reciprocating without delivering any impact to:the work, and that the tool: is thus properly located' without' actual or mental i hazardl}, Thereaftenzthe impact blows are delivered'iat an." amazingly; high. rate by merely pressing; the entire devicer a; little; morev heavihr toward the workagainst the; resistance of the spring: 53; Little" eflo'rtiis-i required to holdthe device the desired position operation 1 on thework-i'because:thereris neltherzviolent vibration norIkick-back' on-the canine. In riveting operations 1 the user proceeds with confidence and ease'due to'the fact that by a sli'ght withdrawal movement ofthedevice or by -the=reiease oi finger pieceli', or both; thedelivery-zof 'impact blows to the tool ceases instantly; Over+driving of rivets "and; damage 'to the work areavoided easily because of this" double 2 control which does not entail removal or thetool? from. its; critical posiftion on'thework; It ispractica-lly impossible to stall the action' ot' the-device-accidentallyjor otherwise. I

The device: is desirably" operated on" a constant fluid; pressure source :oi from fifty to one, hundred pounds. It is economical of Dowerbecause oi'its remarkably rapid delivery oir'blows of'resulateddegrees; oi" impact fonthetooli The speed-of reciprocation of the piston may" be conservatively stated to exceed therate-"ofl alternation of commercially available*'A CI. electric current supply.

Inthe design 01' the; device; it may be" noted that. within limits the increase-of the" sum total area of exhaustports "increases the power of maximum attainable impact: deliverable by'the piston and also enablesthe useaot' weakersprings I-Tforthe piston. v

Various modifications of structure and design are included withinthe spirit of the invention andthetscopeoftheappendedclaim;

What is claimedisi In a selt -cooiing;iand'nonelubricated pneumatic hammer the combination: ois atcasing having acylindricallbor'e; and inlet: andrexh'aust ports respectively" communicating? with. the: bore in the periphery thereoig'i a loosely. fitting: hollowpiston open at. itsrearreciprocabl'y cmounted in said bore in thecasing-and? provided? withaan' annularly; grooved portion providedal with ports communicating -with the hollowinterior. and alter-- natel'yv communicating: with: said inlet" and exhaust; ports as the piston :reciprocates; means exerting: .a. yieldable axial retracting" pressure on.

said piston and means for controlling "airfibw' oi' motive pressureai'r to "said' iniet port', said, piston adaptedior reciprocation in non-contacting: andpressure. air lubricated relation to" saidcylindrical bore. a i

, RICHARD R. BU'I'IS. 

